\documentclass{chowto}

\title{Operating the HMS Shield House Door}
\howtotype{user} % ``expert'', ``user'', ``reference''
%\experiment{Name of experiment} % Optional
\author{H. Fenker}
\category{hms} % Subject area of this document

%\maintainer{Name of person maintaining document} % Optional
\date{April 16, 2003} % Can use \today as the argument

\begin{document}

\begin{abstract}
This document describes the operational procedures for opening
and closing the HMS shield house door.
\end{abstract}


\section{Related {\it Howtos}} 
The following Hall-C {\it Howto} documents may be helpful.

%--DELETE THOSE  DOCUMENTS MENTIONED HERE WHICH ARE IRRELEVANT
User Level Documents-
    \par \indent \indent Base Equipment Checklist \cite{howto:base_equip_checklist}
    \par \indent \indent Operating the SOS Shield House Door \cite{howto:open_sos_door}
    \par \indent \indent Operating the HMS Vacuum Window Shutter \cite{howto:open_hms_shutter}

\section{Door Description}
Normal access to the interior of the HMS shield house is through the
15 ton concrete-and-steel door. 

\section{Door Operation}
The door is moved
by energizing the drive motor attached to it. Once you have it open as wide as you
need, it is suggested that you use the rubber block provided to
chock the door in the open position.
It does tend to drift closed if not restrained. If you find yourself
inside the shield house with the door closed, there are pushbutton
controls inside which you can use to open it (see below).

\subsection{Interlocks}
An interlock prevents access to the HMS detector hut unless the
safety shutter inside the hut has been moved to its `down' position,
such that it covers the vacuum window. This is to prevent people from
accidentally touching the large vacuum window. The door cannot be opened
unless the shutter is already inserted. To prevent the door from
drifting open on its own, a magnetic lock holds it in the closed
position. This lock is de-energized when the {\tt OPEN} control
button is pressed.

\subsection{Motorized Operation}
The door is opened or closed by activating the motor attached to 
its hinges. The control panel for the door is mounted on the
post behind and to your right as you stand in front of the door. A
duplicate set of controls is inside the shield house, to the
right of the door. Press and
hold the button marked {\tt OPEN} and the door will be slowly
opened. Press {\tt CLOSE} to move the door towards the closed
position. Remember that the door will continue to move after
you release the button because of its inertia. It takes about
two minutes to fully open the door or to close it from the
fully opened position. When closing the door, make certain
to keep {\tt CLOSE} pressed until the magnetic lock near
the top of the door engages.


\end{document}

% Revision history:
% $Log: open_hms_door.tex,v $
% Revision 1.2  2003/04/16 13:40:13  saw
% (hcf) Add some detail, remove manual operation section
%
% Revision 1.1  2003/04/04 15:59:47  saw
% Initial Checkin